Hydraulic motor



Dec. 5, 1933. s. H. HoBsoN 1,933,021

HYDRAULIC MOTOR Original Filed June 21, 1929 2 Sheets-Sheet 1 2 Sheets-Sheet 2 S. H. HOBSON HYDRAULIC MOTOR Original Filed June 21, 1929 EEEEEE E Dec. 5, 1933.

M 7m; EMMH/ M Patented Dec. 1933 I UNITED STATES 1,938,021 HYDRAULIC MOTOR Stanley H. Hobso'n, Rockford, Ill., assign'or to Y Geo. D. Roper Corporation, Rockford, 111., a

corporation of Illinois Original application June 21, 1929, Serial No; 372,632. Divided and this application May28, 1931. Serial No. 540,549 V ,2 c aims. (01. 121-15? 1 This invention relates to hydraulic motorsgen erally, and is particularly concerned with one especially designedand adapted for use as a part of a working head for deep, well pumps.

Geared working heads have been objectionable because of the multiplicity of moving parts re-.

quired and the inability to insure adequate lubrication especially .under adverse operating conditions as, for example, in farm installations Where 0 the outfit is called upon to take care of the entire farm pumping service and is seldom, if ever, in,- spected to see if it is getting proper lubrication.

It is, therefore, the principal object of my invention to provide a hydraulic motor as part of the working head for a deep well pump, utilizing oil as the working fluid and designed so that all of the moving parts, the number of which is reduced to a minimum and far below' whatis re.- quired in a geared working head, operate continuously immersed in the oil. In the hydraulic motor there is a reduction in the number of moving parts from the ten or more parts required in the geared type down to practically only one moving part, namely, the working piston, aside,

I 5 of course, from the pilot valve and main valve,

which are reciprocated in timed relation to the piston.

The invention, more specifically. stated, contemplates improvements in the piston and its '3, guiding means for adapting the motor to the operation of a deep well pump; the provision of adjustable stops on the pilot valve stem for the purpose of enabling variation in the length of the stroke of the piston as desired and accordingly control the operation of the pump, and the provision of cushioning springs in connection with the pilot valve to prevent movement of the valve from whichever position the same is operated to by the crosshead.

Other objects and advantages of the invention will appear in the course of 'thefollowing description in which reference is made to the accompanying drawings wherein- Figure 1 is a plan view of a working head utilizing a hydraulic motor made in accordance with my invention;

Fig. 2 is a side view of Fig. l with certain portions broken away and shown in section;

Fig, 3 is a vertical cross-section on a somewhat enlarged scale taken on the line 3-3 of Fig. 2 so as to show the hydraulic motor to best advantage; V

Fig. 4 is a fragmentary sectional detail corresponding to a part of Fig. 3 with the pilot and main valves in altered positions;

1 tion with the pumpdriving shaft.

' Fig. 5 is a horizontal section'on the line 5-5 of Fig. 3 on a reduced scale, and

Fig. 6 is a fragmentary sectional view illustrating a different form of packing means in connec- The same reference numerals are appliedto corresponding parts throughout the views.

This application is a division of my copending application Serial No. 372,632, filed June 21, 1929, now Patent Number 1,906,965, granted May 2, 1933.

The outfit has a base 6 arranged to be set on a suitable foundation over the well casing alongside the drop pipe 7 which, as is well known, isdisposed substantially centrally'in the well casing. An electric motor 8 is mounted on one end of the base, and anoil tank 9, suitably made of sheet metal, is mounted on the other end with the hydraulically-operated Working head 10 disposed therein immersed in the oil with which the tank is filled and which constitutes the working fluid and at the same time serves as a lubricant for such of the parts of the working head as require lubrication, as will be pointedout presently. A light oil is suitable for the purpose inmost cases, and in extremely cold weather this oil; may. be thinned withfkerosen'e if need be; .Theworking head comprises a casting 11 .providing'a working cylinder 12 and a valve chest 13 side by side, the casting being disposed vertically and having lugs 14 on the lower end thereof for boltingtthe same onto the base with the "tank 9 as indicated atl5, thereby making the Working head perfectly rigid. An oil pump 16 made generally along the lines of that disclosed in my application, Serial No. 300,666, filed August 20, 1928, is mounted directly on one side of the valve chest 13 inside the tank 9. Itcomprises an approximately square back plate 17, bolted as'indicated at 18 ontoa flat face provided therefor on theside of the-valve chest, and has a circular'cast-iron housing 19 and face plate 20 securedthereto as by means of bolts 21. Bearings are provided in the back plate and face plate for shafts 22and '23 onto which the intermeshingherringbone gears 24 and 25 are fixed. 100 The latter work inside the casing 19 and have an intake passage 26provided'in' theback plate 1 7 leading to the suction side thereof and a dis charge port27, also provided in the back plate 17 communicating with the pressure side thereof. The port126 communicates at its lower end with the inside of the tank 9 close to the bottom thereof so that the pump will pump oil when there is only very little left in the tank. Thevdischarge port 27 communicates with the intakeiport 28 of the valve chest 13 shown in Figs. 3 and 4 so that is only a stub shaft butthe shaft 22 extends through a bearing hole 29 provided in the casting 11 between the cylinder 12 and valvechest 13, and is long enough to reach-through a stufiing box 30 mounted in the side wall of the tank 9. Theouter end of the shaft 22 has a direct driving connection with the armature shaft 31 of the motor 8 through a coupling 32. A packing nut 33 compresses packing material into a counterbore provided in the side wall of the valve chest 13 where the shaft 22 extends therefrom, so as to prevent the leakage of oil under pressure along the shaft 22 into the tank 9. Another packing nut 34 on the outer end of the stuihng box 30 compresses packing material therein to prevent the leakage of oil from the tank along the shaft 22. Obviously, any suitable packing means may be employed, and instead of that shown, I may employ a quick-seating packingmeans such as that shown in Fig. 6 consisting of a cup leather 33' on the shaft 22 in place of the packing nut 33, and another cup leather 34 I on the shaft 22 at the inner end of the stufiing box 30 with a compression spring 30' disposed therebetween so that thejone leather seals the pump against pressure'loss', and the other leather seals the tank against oil leakage, both leathers being held seated by the same spring. 'The direct drive through the coupling 32 and the sealing of the oil pump 16 against pressure losses so that the full delivery of the pump is available for the operation of the working head, are both items which,

of course, tend toward higher operating fliciency.

, The casting 11 of the working head 10 has a castyoke member 35bolted as indicated at 35 on the upper end thereof, the base 37 of said part serving. as a closure'for the upper end of the working cylinder 12. A plate 38 is bolted, as indicated at 39, to the casting 11 to close the lower end of the cylinder 12. 'A hollow piston 10, having a. tubular rod 41 preferably formed integral therewith, is reciprocable in the cylinder 12 with the rod 41 extending'upwardly through a center hole s2 provided, in the base 37 of the yoke 35. Rings 43 in'thepiston 10 reduce the oilleakage' past the piston to a minimum, so that practically all of the available pressure is effective .in the operation'of the piston up or down in the cylinder 12. A cup leather 44, suitably clampedinplace in the bolting of the yoke mem ber 35,-.fits snugly around the rod 41' and minimizes leakage from the cylinder past the rod. Any oil that manages to escape at this point will drain back into the tank so that it is not lost. The, rod 4l, te lescopes with a guide post 45 suitably secured at its upper end in the boss 46 on the upper, end of the yoke member 35 and provided with. one or more piston rings 4'7 on its lower'end to prevent the escape of f oil from the inside of the piston and rod about the same. The

-' rod 41, itwill benoted, has ports 48 cored'therein next to the piston 40 so as to place the inside of the piston and rod in open communication with the cylinder 12 on one side. of the piston. The ports 48 have this advantage: There is substantially. the same area on both sides of the piston subjected to the pressure .of theoil delivered to the cylinder so that the piston is moved downwardly with substantially the same force as it is moved upwardly, which, of course, makes the working head suitable for use withadouble act ing pump. The fact that the inside of the piston rod is in communication with the cylinder makes the ultimate volumetric capacity of the cylinder on the upper side of the piston just about the same as that on the lower side so that the piston is moved downwardly only slightly faster than it is moved upwardly, assuming a constant rate of oil delivery. The fact that the inside of the rod ll is always filled with oil below the guide post insures adequate lubrication of the guide post because there is bound to be some oil which will not be scraped off by the rings 17. Any surplus oil escaping from the upper end of the rod 41 will, of course, drain back into the tank so that there is no waste. The rod 41 has a crosshead 49 fastened to the upper end thereof having connection at one end with the plunger rod 50 of the pump and at the other end with the stem 51 of a pilot valve 52. The crosshead as, as shown in Fig. 5, is suitably cast in two symmetrical parts. The two parts have annular ribs 53 cast in the center hub 54 thereof to fit in annular grooves 55 machined in the upper end of the rod ll. Thus, when bolts 56 are inserted through the two halves of the crosshead and tightened to cause the ribs 53 tolwedge in the grooves, a rigid connection is made between therod'and the crosshead. The outer ends of each of the halves of the crosshead provide half round hubs 5'7 and 58 at Opposite ends so that when the two halves of the crosshead are bolted together as just stated,c onnection is made with the plunger rod'50 at one end and with the stem 51 at the other end. The plunger rod50 has nuts'59 threaded on the upper end thereof above and below the crosshead 49arranged to jam against the top and bottom of thecrosshead to make the plunger rodrigid upper collar 60 to raise the pilot valve 52 to the extent indicated in dotted lines in Fig. 3, that is, to the position shown in Fig. 4. The valve is shown in full lines in Fig. 3*in the position to which it is moved by the crosshead when the latter engages the lower'collar 60 atthe lower end of the stroke of the piston 40; The shifting of the pilot valve 52, as will next be described, causes the shifting of the main valve 62 to change the relation of the inlet port 28 in the valve chest 13 reports 63 and fiicommunicating with the upper and lower endsof the cylinder 12, respectively, so that on the upstroke the port 64 communicates with the inlet port23 while oil is exhausted from the upper port 63, and vice versa ,on the down stroke. In passing, it 'will be noted that the plunger rod 50 has the lower end thereof entered in a guide 65 bolted, asindicated at 66,

onto the head 67, which in turn has the drop pipe lower end of the plunger rod 50 has the upper end of the pump rod 70 coupled therewith, as indicated at 71, in the usual way. An arm 72, fastened to the plunger rod 5i) near the upperend thereof, provides connection between the rod 50' and another rod 73 ahixed to a plunger 74 in the air compressor cylinder '75 mounted on theihead '67 in the usual. way; The pet Icock. 7 6 is arranged; to be left open i'n the normal operation of pump except when additio air is needed in theistorage'tank, at which timethe' pet cock is closed, so that air trapped in front of the plunger 'Hlon the upstroke thereof is forced into the tank' off t o nstr am a mann Wi khQWn in thisart. I

Thevalve ne tisflias"tli man-s eet, a,

51'Ztherethrough, the pilot valvef'52 being ,reciprocable inside the main-valvej62. "TWO: internal annular grooves 81 and'82 are provided'inthe Ina-in valve .62 between'ilth reej external annular grooves 83, .84 andl8'5 .provided on said valve, Oneor more ports 86in said valvefafford communication between the inside thereof and the annular chamber in the valve'chest affordedby the groove 84; Likewiseione or'morepoits-S'l' in'the upper end of said valve affordcorrununication, between the inside thereof and the cham ber in the valve chest afiorded bythe annular groove 83, andv one or more ports 88- in the lower end of said valve afford communication "between the insideof the valve and thechamber inthev valve chest afiorded by the annular groove 85.

About the only othergfeature ofthe main valve 62 requiring mentionfis' the provision ofa longitudinal passage 89 provided in a longitudinal boss on the. upper; end thereof, providing communioationbetween-the internal annular groove 81 and the upper end of the valve chest above the valve 62, and another longitudinal passage 90 at the lower end of said valve affording communication between the internal annular groove 82 and the lower end of the valve chest below the valve 62. ,Now, the pilot valve 52 has two annular flanges 91 and 92 formedjintegral therewith in a predetermined spaced relation to one anotherh'avin'g a close working fit in the bore '79 of the main valve 62 -The function of the pilot valve 52 is to place the port 86 in communication either with the groove 82, as shown in Fig. 3, or with the groove 81,,as shown in Fig. 4. When port 86 is in communication with groove 82, the main valve 62 is shifted hydraulically'by reason of the fact that the inlet port 28 of the valve chest is then placed'in communication by way of port 86, groove-82 and passage 90 with the lower end of the valve chest below the valve 62. On the other hand, when the port 86 is placed in communicationwith the groove 81, as shown in'Fig. 4, the inlet port 28 is placed in communication with the upper end of the valve chest 13 by way of port 86, groove 81 and passage 89. In the first caseythe valve 62 is naturally moved upwardly and held in that position under pressure of the working fluid, and

in the other case it is moved' downwardly and held in that position.

In operation, assuming that the pilot valve 52 has been moved to the lower position shown in Fig. 3, that is, when the piston 40 arrived at the lower end ofits stroke, the main valve 62 is raised by reason of the port 86 being placed in communication with the groove 82, so that oil is delivered from the inlet port 28 to the 1 lower end of the valve chest by way of port 86, groove 82 and passage 98'. With the main valve 62. in.its upper position,-as it is shown i'n Fig. 3, oil is delivered to the lower end of the ,cylinderf12frorn the inlet port 28 through portffi l. Thus, the piston lo is forced upwardly, and, of'course, raises the pump rod 70with it. The 'oilabove the piston is dislc'harged'through po1t63 which, inthe. upper position of the main valve? .62, communicateswith the exhaust-port 93 provided in the wall of the valvelch est near the lower end thereof. When the piston 40 reaches the upper end of its'stroke, itscrosshead 49 shifts the pilot valve 52 in the manner previously described, and the instant the port 86 is brought into communication. with the groove 81,'the main valve 62 is moved to the lower position shown in Fig. 4 under the actionof'oil delivered to the upper end of the valve chest from the inlet port 28 throughport 86, groove 81 and passage 89. The shifting of the main valve 62 is practically instantaneous so that there is no noticeable dwell of the crosshe'adat either end of the stroke. The change indirection is furthermore not accompanied with, any slowing down of the crosshead as it approaches the end of the stroke. With' thehaain valve 62in the lower position, the inlet port 28 communicates with port 63, so that oilis supplied to thefupper' end of the cylinder 12 to force the piston down wardly. 'Atthesame' time the port 64, com-- municates with the exhaust 'port '9l[providedfin the wall of the valve'schestnear .theupper end thereof 'so that the oil in the cylinder12' below the piston 40is discharged back into the. tank;

A shield wall 95 is preferably cast integral with the wall of the valve'che t 13 to provide apassage 96 leading from the exhaust port 94 down to and past theilower' exhaust port 93; It is found that without such a shield there is danger of oil being lost by reason of its discharge against the side of the tank with considerable force, the spray so produced being bound to throw some of the oil out of the tank; The pilot valve 52, it is found, will not tend to move back of its own accord from a position to which it has been moved by the crosshead 49, because there is always some oil on both sides of the flanges 91 'and 92 in the bore '79 of the main valve 62 and the oil on the opposite side of flange 91 or 92 from the pressure port 86 is trapped the moment the main valve is shifted, as appears in Figs. 3 and 4. However, there is frequently a tendency for the pilot valve to move beyond the position to which it is shifted by the crosshead owing to a building up of pressure behind the flange 91 or 92 occasioned by leakage ofoil between the relatively moving parts, due to slight discrepancies in the machining of the parts to size, or due to other causes which are sometimes dimcult to explain. Forthat reason, I have in certain cases found it a good practice to provide a compression spring 97 below the collar 60 and another compression spring 98 above the flange 91 fitting about the stem 51 of the pilot valve 52. These springs are fairly stiff, and when the pilot valve is shifted to its lower position, as shown in full lines in'Fig. 3, the spring 97 resists any tendency for the valve to move beyond the position shown, and when the pilot valve is moved to its upper position, as shown'in Fig. 4, the spring 98 keeps it from moving beyond that position. It is believed to be obvious that the mere adjustment of the collars 60 closer together or farther apart on the stem 51 of the, pilot valve 52 will result in a corresponding shortening or lengthening of the stroke of the piston 40. In the particular design shown, thestroke may be changed from a short stroke of 2" to a long stroke of 6", but it will be evident that a muchgreater length of stroke might be provided for by simply providing a longer working cylinder 12 and a correspondingly longer guide 45. The outfit is, therefore, adaptable to practically any requirements that may be encountered.

It is believed the foregoing description conveys a clear understanding of my invention and all of the important objects and advantages. Manifestly, various changes in design and construction might be made without seriously departing from the spirit and scope of the invention. The appended claims have, therefore, been drawn with a view to covering all legitimate modifications and adaptations.

I claim:

1. In a device of the character described adapted to operate a reciprocating member, the combination of a working cylinder, a piston reciprocable therein having a reduced tubular rod extending therefrom through an opening provided in one end of the cylinder, said rod having a crosshead mounted on the outer end thereof arranged to be connected with the member to be operated for reciprocation of the latter, 'a

., yoke mounted on the end of said cylinder, a

reduced, elongated guide post carriedthereby on which the outerend of said piston rod is arranged to telescope substantially the full length of the post for'lateral support, and means for alternately but successively supplying pressure fluid to one end of the cylinder and then to the other and simultaneously exhausting fluid from the opposite end, said piston rod having one or more ports providing communication between the insideof the piston rod and the cylinder behind the piston, for the purposedescribed.

2. In a fluid operated motorof the character cylinder ports and simultaneously between the other cylinder port'and an exhaust port provided in the valve chest, and vice versa in the other operative position of said valve, and a pilot valve serving to control the port provided in the main valve so that pressure fluid from the inlet port is supplied alternately to opposite ends of the valve chest to shift the main valve under fluid pressure from one operative position to the other, means operated in timed relation with the piston for positively shifting the pilot valve from its one operative position to its other, and spring means effective when the pilot valve is brought to either limit position for yieldingly restraining the pilot valve from movement beyond either of the limit positions, said spring means serving to facilitate movement or the pilot valve from one limit position toward the other.

STANLEY HOBSON; 

